The present invention relates to a method of treating a food product in a container to reduce or inhibit a microbial population on the food product, involving applying to the container an antimicrobial solution (applied in an amount effective to reduce or inhibit the microbial population), and placing the food product in the container. The present invention also relates to a system for treating food products, involving a bagging system, a spray system, and a rotating assembly for returning a spray wand to a resting position.
Microbial contamination of food remains a major problem in the food processing industry. For example, in recent years there have been at least three large outbreaks of listeriosis in the United States that were associated with ready-to-eat (RTE) frankfurters and/or delicatessen-type meats (Morbidity Mortality Weekly Report, 47: 1085-1086 (1998), 49: 1129-1130 (2000), 51: 950-951 (2002)). During this same time period there have also been several large recalls due to contamination of RTE meat and poultry products with Listeria monocytogenes. The economic loss due to recalls of meat and poultry products contaminated with this pathogen alone is estimated at $1.2 to $2.4 billion dollars per year in the United States (Thomsen, M. R., and A. M. McKenzie, American Journal of Agricultural Economics, 82: 526-538 (2001)). In addition, food surveys conducted in the United States between 1990 and 2003 involving ˜100,000 samples estimated the prevalence of L. monocytogenes at 1.6% to 7.6% in meat, fish, and vegetable products, most of which were RTE foods (Gombas, D. E., et al., Journal of Food Protection, 66: 559-569 (2001); Wallace, F. M., et al., Journal of Food Protection, 66: 584-591 (2003)).
In response to the frequency and magnitude of food recalls, as well as the number and severity of infections, the USDA Food Safety and Inspection Service (USDA/FSIS) established rules/guidelines for RTE meat and poultry manufacturers to better control microbial growth (Federal Register, 68:34207-34254 (2003)). This ruling provides manufacturers with three options for determining the degree to which regulatory testing would be implemented for their plant/product: (1) alternative 1—use of both a post-process lethality step and an antimicrobial to control outgrowth (lowest testing frequency); (2) alternative 2—use of either a post-processing lethality step or an antimicrobial to control outgrowth (moderate testing frequency); or (3) alternative 3—use of appropriate sanitation alone (most testing). These guidelines make it imperative to identify and implement post-process interventions for lethality and/or inhibition of microbes such as L. monocytogenes in food products (e.g., RTE meat and poultry products).
Various chemicals are antagonistic towards microbes such as L. monocytogenes in foods when used in bath, dip, or spray applications on the meat product and/or when added as an ingredient into the meat product (Crozier-Dodson, B. A., et al., Food Safety Magazine, Jan. 24-27, 2005, pages 75-76). For example, potassium lactate and sodium diacetate used alone or in combination are effective at controlling L. monocytogenes in RTE meats (Barmpalia, I. M., et al., International Journal of Food Microbiology, 67: 2456-2464 (2004); Bedie, G. K., et al., Journal of Food Protection, 64: 1949-1955 (2001); Buncic, S., et al., Journal of Food Safety, 15: 247-264 (1995); Mbandi, E., and L. A. Shelef, Journal of Food Protection, 64: 640-644 (2001); Porto, A. C. S., et al., Journal of Food Protection, 65: 308-315 (2002); Seman, D. L., et al., Journal of Food Protection, 65: 651-658 (2003)). Sodium, potassium, and calcium lactates have been approved for use as flavorants, shelf-life extenders, and/or antimicrobials. Acidifiers such as acidified sodium chlorite (ASC) are effective for controlling L. monocytogenes on beef carcasses (Castillo, A., et al., Journal of Food Protection 62: 580-584 (1999) and broiler carcasses (Kemp, G. K., et al., Journal of Food Protection, 63: 1087-1092 (2000), as well as on cook-in-bag turkey breast (Luchansky, J. B., and J. E. Call, Hot water post-process pasteurization of cook-in-bag turkey breast treated with and without potassium lactate and sodium diacetate and acidified sodium chlorite for control of Listeria monocytogenes, Journal of Food Protection, submitted). Moreover, ASC has been approved as an antimicrobial on processed, comminuted, or formed meat products. Other acidifiers (e.g., acidic calcium sulfate (ACS) which is formulated with organic acids and calcium sulfate) are effective in reducing the levels and controlling the outgrowth of L. monocytogenes on the surface of frankfurters during prolonged refrigerated storage (Nunez de Gonzalez, M. T., et al., Journal of Food Protection, 67: 915-921 (2004); Keeton J. T., et al., Antimicrobial effects of surface treatments and ingredients on cured RTE meat products, Final Report: American Meat Institute Foundation, Washington, D.C. (2002)). Currently, ACS is considered GRAS (Generally Recognized As Safe) and is approved for use in meat products. As a final example, in more limited studies, surfactants such as lauric arginate (LAE) were effective at inhibiting growth of L. monocytogenes in cooked meats during refrigerated storage (Bakal, G., and A. Diaz, Food Quality, 12(1): 54-61 (2005)). Although the ingredients in LAE have been self-affirmed as GRAS, at present it is not approved for use in meats.
Almost all vacuum packaged meats produce some amount/volume of purge after vacuum packaging. Purge is the fluid that forms while, for example, a RTE product is under vacuum conditions in the package. The fluid comes from internal moisture that is in the meat product which migrates to the area between the surface of the product and the inside of the package. Currently, antimicrobials are directed (e.g., injected) internally into the product prior to processing or applied to the surface of the product during processing. The antimicrobial effect is thus directed to the meat product itself. However, such treatments are not totally effective. Thus there is a need for improved methods for microbial control in packaged food products.